Method of manufacturing water-soluble polymers, polymers manufactured thereby, and uses of said polymers

ABSTRACT

Homopolymers and/or copolymers are manufactured by polymerizing ethylenically monounsaturated monomer(s) in an aqueous solution in a reaction vessel containing compounds which contain a phosphorus atom of degree of oxidation less than 5, phosphorous compounds being introduced in amounts of 0.005-0.49 gram-atom phosphorus per mol of unsaturation in said ethylenically unsaturated monomer(s) in the presence of hydrogen peroxide and in the absence of any agent(s) which decomposes hydrogen peroxide thereby forming free radicals, in the absence of any other generator of free radicals, and in the absence of any per salt and/or any other transfer agent.

A division of application Ser. No. 09/219,887 filed Dec. 24, 1998, nowU.S. Pat. No. 6,063,884, which is a division of application Ser. No.08/897,572 filed Jul. 21, 1997, now U.S. Pat. No. 5,891,972.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of manufacturing homopolymersand/or copolymers, in an aqueous solution of ethylenicallymonounsaturated monomers, e.g. acrylic and/or vinylic monomers, suchthat, for each monomer, one can achieve a residual monomer concentrationless than or equal to 300 ppm (based on the weight of the raw product),wherewith the concentration of the products is at least 38%; andwherewith these results can be achieved regardless of the monomer(s)used, and at the end of the polymerization, without the need for anyintervening treatment.

The invention also relates to the homopolymers and/or copolymersmanufactured by the described method; and the use of said homopolymersand/or copolymers, as:

milling agents and/or dispersants in aqueous suspensions of mineralmaterials; or

sequestering agents and/or precipitation inhibitors and/or inhibitors ofmineral incrustation (particularly with respect to heat transfersurfaces in industrial or household systems); or

fluidifying agents for aqueous suspensions based on non-saline or salinewater, which suspensions are used as drilling fluids (muds) and the likein the areas of civil engineering, construction, public works, mineralsprospecting, and petroleum production; or

stabilizers for suspensions of zeolites; or anti-scaling agents anddispersant agents, in detergent formulations containing hypochloritecompounds, wherewith the subject polymers do not destabilize the“chlorometric index” of said hypochlorite compounds; or

“builders” in detergent compositions; or

water retention agents in the paper industry.

The invention further relates to the abovementioned aqueous suspensionsof mineral materials, having characteristics of long term stability andhigh concentrations of the mineral materials; and the use of thesuspensions in areas such as paper, paints and other coatings,detergents and other cleaning agents, ceramics, mineral drilling andproduction (e.g. drilling-mud compositions), and other sectors whichemploy such suspensions.

2. Description of the Background

Various methods have long been known for homopolymerization, insolution, of acrylic and/or vinylic monomers, e.g. (meth)acrylic acid,maleic anhydride, and acrylamide; and for copolymerization, in aqueoussolution, of acrylic acid with monoethylenically unsaturated comonomerssuch as, e.g., maleic anhydride, itaconic acid, acrylamide,(acrylamidomethyl)propanesulfonic acid, and acrylate esters. However,none of these methods is entirely satisfactory in the light of currentand/or expected environmental regulations, particularly regulationsgoverning the residual monomer content in the polymer in a givenapplication, or requirements as to the color and/or odor of the product.

Eur. Pats. 0,668,298 and 0,608,845 describe methods of copolymerizationwhich, unless subsequent treatments are employed, result in residualmonomer contents which exceed 1000 ppm. These methods would not meet thestandards demanded in the current market.

Eur. Pat. 0,618,240 discloses a method enabling production of polymerswith lower residual monomer content, as do Eur. Pats. 0,398,724,0,510,831, and 0,663,408; however, all have fundamental practicaldisadvantages connected with the method, or disadvantages such as:

the use of metallic salts which promote decomposition reactions ofhydrogen peroxide, e.g. the Fenton reaction, which often result(s) inultimate products which are undesirably colored and which contain metalsalts which are environmental pollutants;

the use of persulfates which undergo decomposition because of theapplication of heat or because of redox reactions, resulting in ultimateproducts which undesirably contain sulfur; and

the use of organic initiators, e.g. organic peroxides, particularlybenzoyl peroxide, which result in the production of undesirableby-products such as certain nitrogen compounds.

U.S. Pat. No. 4,301,266 discloses a method of manufacturing acrylic acidpolymers, with the disadvantage that one must use a solvent of theisopropanol type and must operate at elevated pressure.

Also known to those skilled in the art is U.S. Pat. No. 4,621,127, whichdiscloses a method of copolymerization. The method is costly andlengthy, and requires the use of chain regulators to prepare lowmolecular weight polymers.

SUMMARY OF THE INVENTION

Accordingly, one object of the invention is to provide a method whichenables the production of dissolved polymers which are colorless,odorless, and which are accompanied by very low (minimum) amounts ofresidual monomers and undesirable organic by-products.

Another object of the invention is to provide a milling agent and/ordispersant for aqueous suspensions of mineral materials, which enablesproduction of concentrated aqueous dispersions of mineral particles,which dispersions have relatively low viscosity and are durably stableeven without agitation.

Still another object of the invention is to provide a sequestering agentand/or precipitation inhibitor and/or inhibitor of mineral incrustation,using a copolymer of the described type having a molecular weight lowenough to be adapted to such applications.

Yet another object of the invention is to provide

a fluidifying agent for aqueous suspensions which are used as drillingfluids (muds) and the like; or

a stabilizer for suspensions of zeolites; or

an anti-scaling agent and dispersant agent, for use in detergentformulations containing hypochlorite compounds, wherewith said agentdoes not destabilize the “chlorometric index” of said hypochloritecompounds; or

a “builder” for detergent compositions and the like.

Still another object of the invention is to provide aqueous suspensionsin paper pulp processing, processing of pastes and slurries in sugarmanufacture, paper coating, ceramics manufacture, detergent formulation,and formulation of drilling muds and the like.

Briefly, these objects and other objects of the present invention ashereinafter will become more readily apparent can be attained in amethod of polymerization in which compounds containing a phosphorusatom, having a degree of oxidation less than 5, are introduced inamounts corresponding to 0.005-0.49 gram-atom phosphorus per mol ofunsaturation in the monomer(s) to be polymerized, into the reactionvessel or into the starting monomer mixture in the reaction vessel asinto the reaction vessel, prior to the start of the polymerization, saidintroduction occurring:

in the presence of hydrogen peroxide and

in the absence of any agents, which decompose hydrogen peroxide to formfree radicals, such as metals or metal salts, which agents are deemednecessary by the art to satisfactorily achieve such decomposition,further, in the absence of any other generator of free radicals, and inthe absence of any per salt and/or any other transfer agent.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Whereas the prior art to which the present invention relates describesmethods of polymerization which make use of decomposition reactions ofhydrogen peroxide of the type of the Fenton reaction, or employsreactions of thermal or redox decomposition of initiators currently inuse, it has now been found, and quite surprisingly, that the use of acompound containing a phosphorus atom of degree of oxidation less than5, when introduced in amounts corresponding to 0.005-0.49 g-atomphosphorus per mol of unsaturation in monomers in an aqueous reactionmedium enables:

homopolymerization of a monomer such as (meth)acrylic acid or maleicacid, or

copolymerization of maleic acid or a copolymerizable monomer, withacrylic acid or a copolymerizable monomer, with the addition solely ofhydrogen peroxide, without the presence of agents which promotedecomposition of hydrogen peroxide to form free radicals, e.g. metals ormetal salts, such as salts of Cu, Fe, Co, Ni, Zn, W, Ce, Mo, Zr, ormixtures of these, which agents are deemed necessary in the art in orderto satisfactorily achieve such decomposition, e.g. in the familiarFenton reaction, and further without the presence of organic initiators,e.g. benzoyl peroxide, and further without the presence of per salts,e.g. persulfates, and further without the presence of other transferagents e.g., thio compounds, alcohols, halides, amines, and the like.

The copolymerizable monomers are selected from the group consisting of(meth)acrylic acid, itaconic acid, crotonic acid, fumaric acid, maleicacid anhydride, isocrotonic acid, acronitic acid, mesaconic acid,sinapic acid, undecylenic acid, angelic acid; esters of the aforesaidacids; (acrylamidomethyl)propanesulfonic acid, acrolein,(meth)acrylamide; (meth)acrylamidopropyl trimethylammonium chloride,(meth)acrylamidopropyl trimethylammonium sulfate, ethyltrimethylammonium chloride (meth)acrylate, ethyl trimethylammoniumsulfate (meth)acrylate, acryloyl (trimethylammonium chloride),acryloyl(trimethylammonium sulfate), or the non-quaternized homologs ofany of these; dimethyldiallyl chloride, sodium methallyl sulfonate,ethylene glycol (meth)acrylate phosphate, propylene glycol(meth)acrylate phosphate, and vinylpyrrolidone.

The present method enables (co)polymerization in an aqueous phase in acontinuous or semicontinuous or batch process, yielding a copolymerhaving a residual monomer content of less than or equal to 300 ppm onthe basis of the raw product for each monomer. The concentration of theproduct copolymers is at least 38% regardless of the amounts of themonomers by weight, and after the termination of the polymerization, itis not necessary to resort to any of the customary treatments well-knownto persons skilled in the art such as distillation or adding excessoxidizing or reducing agent following the polymerization.

The present method of manufacturing homopolymers and/or copolymers, inan aqueous solution, from ethylenically monounsaturated monomers, suchas acrylic and/or vinylic monomers, occurs with compounds which containa phosphorus atom of a degree of oxidation less than 5, which areintroduced into the reaction medium in amounts corresponding to0.005-0.49 g-atom phosphorus per mol of unsaturation in the monomerspolymerized,

in the presence of hydrogen peroxide and

in the absence of any agents which promote decomposition of hydrogenperoxide to form free radicals, and further, in the absence of any othergenerator of free radicals, and in the absence of any per salt and/orany other transfer agent. More particularly, in the method, all or partof the necessary quantity of the compound containing a phosphorus atomof degree of oxidation less than 5 is introduced into the reactionvessel or into the starting mixture in the reaction vessel, prior to thestart of the polymerization, which introduction may occur in thepresence of all or part of the monomer(s) which are to undergopolymerization, which monomer(s) if then present may be present as acidsor in a partially or completely neutralized state by neutralization witha basic solution. Further the method results in the production ofhomopolymer(s) and/or copolymers without addition of metals or metallicsalts, which metals or metallic salts initiate the decomposition ofhydrogen peroxide.

In the present method of copolymerization, copolymerization isconducted, regardless of the proportions by weight of the monomers, byintroducing into the reaction vessel or into the starting mixture in thereaction vessel, all or part of the quantity of the compound containinga phosphorus atom of degree of oxidation less than 5, which compound isselected from the group consisting of sodium hypophosphite andhypophosphorous acid, the quantity being determined depending on thedesired molecular weight of the polymer, and the introduction may be:

in the presence all or part of the monomer(s) to be polymerized, whichmonomer(s) if then present may be present as the acids or in a partiallyor completely neutralized state provided by neutralization with a basicsolution, and

generally in the presence of sufficient added water to obtain ahomogeneous solution.

The base used may be sodium hydroxide, potassium hydroxide, or lithiumhydroxide, which may be added in the form of a solution or as pellets.

It should be noted that in the present method the expected molecularweight of the copolymer (in the case of manufacture of a copolymer) isnot directly a function of the amount of hydrogen peroxide employed, butrather is governed by the relative amount of phosphorus employed and theconcentration of the medium.

In the present method when homopolymerizing acrylic acid, methacrylicacid, or maleic acid, homopolymerization is conducted by combining themonomer, the hydrogen peroxide, the compound containing a phosphorusatom of degree of oxidation less than 5, the additional water, andpossibly one or more of the abovementioned bases. In particular, thefollowing procedure may be used in which the reactor is preheated and ischarged with:

all or part of the total amount of the monomer to be polymerized,

all or part of the total amount of the compound containing a phosphorusatom which is sodium hypophosphite as hypophosphorous acid, in an amountdetermined by the desired molecular weight, and

a quantity of water as needed to prepare a homogeneous solution.

Following this the hydrogen peroxide is injected into the reactor. Abase comprising one or more of the abovementioned bases is added in amanner and at a time or times such that the injection of the hydrogenperoxide will be in the presence of said base.

Then at the end of the homopolymerization or copolymerization of areaction duration of preferably 2 hr or less, the copolymer obtained iscooled and then is recovered without further treatment, to be useddirectly in the form recovered.

The copolymer may also be partially or completely neutralized by one ormore neutralizing agents having a monovalent or polyvalent function,e.g. agents selected from the groups consisting of:

alkali cations, particularly those of sodium and potassium, and alsoammonium ion;

the primary, secondary, or tertiary amines, aliphatic and/or cyclic,e.g. mono-, di-, and triethanolamine, mono- and diethylamine,cyclohexylamine, and methylcyclohexylamine;

the divalent alkaline earth cations, particularly those of magnesium andcalcium, and the divalent zinc cation;

the trivalent cations, particularly aluminum; certain cations of highervalence; and

cations of primary and secondary amines, aliphatic and/or cyclical, e.g.cations of monoethylamine, diethylamine, cyclohexylamine,methylcyclohexylamine(s); and combinations thereof.

The polymer may also be treated by any known means to eliminate thewater, particularly whereby the polymer is isolated in the form of afine powder and made use of as said powder.

The polymers obtained from the present method have a residual monomercontent by 300 ppm on the basis of the raw product for each monomer, andthe dry matter content is at least 38% regardless of the monomerproportions employed.

The residual monomer content is determined by an HPLC method withinternal standardization, using an HPLC apparatus having a UV andvisible light detector enabling operation in the range 180-220 nm, andemploying a “Microbondapak” chromatographic column.

The copolymers intended to be used as milling agents, dispersants,fluidifying agents for drilling fluids, and/or Theological modifiers indetergent formulations of the invention have specific viscosity, definedinfra as less than or equal to 10, and preferably less than or equal to3.

In the case the present copolymers are intended to be used for treatmentof industrial and/or household waters, e.g. to confer anti-scaling andanti-corrosion characteristics, or are intended to be used in the areasof reverse osmosis and ultrafiltration for completing of cationspresent, the specific viscosities of the copolymers are in the range0.10 to 10.

The “specific viscosity” referred to is symbolized by the letter p, andis determined in the following manner:

A solution of the polymer is prepared comprising 2.5 g dry polymer and50 mL of doubly deionized water. Then a capillary viscometer having aBaume constant of 0.000105, operating in a 25° C. temperature bath, isused to measure:

the efflux time of a given volume of said solution containing thecopolymer and

the efflux time of the same volume of doubly de-ionized water, notcontaining the copolymer.

The specific viscosity μ is then defined by the following relation:

μ=[(efflux time of the polymer solution)−(efflux time of the doublyde-ionized water)]÷(efflux time of the doubly de-ionized water).

For homopolymers of acrylic acid, the measurement of the specificviscosity is determined by comparison of

the efflux time of a given volume of a solution of 2.5 g of thecorresponding sodium polyacrylate (dry) in 50 mL of a 60 g/L aqueoussolution of sodium chloride to

the efflux time of an equal volume of aqueous sodium chloride solutionwithout the polyacrylate.

The specific viscosity is then given by:

μ=[(efflux time of the polymer solution)−(efflux time of the NaClsolution)÷(efflux time of the NaCl solution).

In both cases the capillary tube is generally chosen such that theefflux time of the doubly deionized water or the NaCl solution withoutthe polymer and/or copolymer is c. 90-100 sec.

The resulting specific viscosity measurements are very precise.

In practice, a dispersion is prepared from the mineral substance to bedispersed, by introducing said substance into an aqueous solution of thepresent dispersant which solution has been prepared with agitation. Themineral substance may be any of a wide range of materials, e.g.: naturalor synthetic calcium carbonate, dolomite, calcium sulfate, titaniumdioxide, lamellar pigments such as mica, and/or kaolin, and/or othermaterials having the characteristic that they must be prepared insuspension and dispersed in order to be utilized in a given application.Some of the very diverse areas of application which might be mentionedare: paper coating; pigmentation of paints; ceramics manufacturing;preparation of drilling muds; and preparation and use of detergents.

The mineral substance may be finely comminuted using comminuting bodies,in an aqueous medium containing the milling agent. For the finecomminution, an aqueous suspension of the mineral substance is formedwherewith the mineral substance has initial particle size not greaterthan 50 micron and is present in an amount such that the dry mattercontent of said suspension is at least 70 wt. %.

The comminuting bodies, advantageously having particle size(s) in therange 0.20 to 4 mm, are added to the suspension of the mineral substanceto be comminuted. The comminuting bodies are generally in the form ofparticles of widely diverse materials, e.g. (inter alia):

silicon oxide, aluminum oxide, zirconium oxide, or mixtures thereof;

hard synthetic resins; and

steels.

An example of the composition of such comminuting bodies is given in Fr.Pat. 2,303,681, which describes comminuting bodies comprised ofzirconium oxide in the amount of 30-70 wt. %, aluminum oxide 0.1-5 wt.%, and silicon oxide 5-20 wt. %. The comminuting bodies are added to thesuspension in an amount such that, preferably, the ratio between theweight of the comminuting material and the weight of the mineralsubstance undergoing comminution is at least 2:1, particularlypreferably in the range 3:1 to 5:1.

The mixture of the suspension and the comminuting bodies is thensubjected to mechanical agitation, of the sort provided in a classicalcomminuting mill with micro-elements.

The present polymeric milling agent and/or dispersant is also introducedinto a mixture comprised of the aqueous suspension of the mineralsubstances to which the comminuting bodies have been added. The amountof the polymer employed is 0.2 to 2 wt. %, based on the dry weight ofsaid polymer and the dry weight of the mineral substance undergoingcomminution. The time needed to finely comminute the mineral substancesvaries according to the nature and amount of said mineral substances,the mode of agitation employed, and the temperature of the medium duringthe comminution.

Having generally described this invention, a further understanding canbe obtained by reference to certain specific examples which are providedherein for purposes of illustration only and are not intended to belimiting unless otherwise specified.

EXAMPLE 1

The objective here is to illustrate an embodiment of the invention inwhich homopolymers of acrylic acid are prepared in the absence of anymetal or metal salt, in which hydrogen peroxide and acrylic acid areadded simultaneously and in parallel to a preheated polymerizationreactor which has been charged with:

(i) water;

(ii) (possibly) part or all of the hypophosphite or hypophosphorous acidneeded; and

(iii) (possibly) part of the acrylic acid, which acrylic acid may bepartially pre-neutralized by, e.g., sodium hydroxide.

Experiment No. 1:

A starting mixture comprised of 132 g of 100% acrylic acid, 132 g of 50%sodium hydroxide, 77 g of sodium hypophosphite, and 200 g of water wascharged, at ambient temperature, to a glass 2 L reactor having astirrer, a thermometer, and cooling means.

As the temperature in the starting mixture increased, the two charges tobe introduced in parallel over a period of 2 hr are prepared.

The first such charge comprises 1024 g of 100% acrylic acid, in onebeaker, and the second charge comprises 40 g of hydrogen peroxide, whichcorresponds to 130 volumes free oxygen, plus 120 g water, said secondcharge being prepared in a second beaker.

These charges are added gradually to the reactor over 2 hr at 95° C.,following which is obtained a polymer in a solution which is clear andcolorless. The polymer is then neutralized by adding sodium hydroxide ofconcentration 50%, to a pH of 8.6. The polyacrylate thus obtainedcorresponds to a homopolymer of the invention having a specificviscosity of 0.64 and a dry matter content of 50.6%. The residualcontent of acrylic acid is 260 ppm determined with respect to the rawproduct, according to the above-described HPLC method.

Experiment No. 2:

This experiment is carried out with the same apparatus, the same mode ofoperation, and the same quantities of reactants as described inExperiment No. 1, with the exception that the amount of 130 volumes ofhydrogen peroxide, which is employed, is changed from 3.46 wt. % of theamount of acrylic acid to 6.9 wt. % of the amount of acrylic acid.

The colorless polyacrylate obtained has a specific viscosity of 0.70, adry matter content of 45.4% after neutralization to pH 8.6, and aresidual acrylic acid content of 10 ppm determined on the raw product bythe analytical method used in Experiment No. 1.

Experiment No. 3:

This experiment is carried out with the same apparatus and mode ofoperation as Experiment No. 1, but the amount of hypophosphite employedcorresponds to 0.068 gram-atom phosphorus per mol of monomer to bepolymerized, and the amount of the hydrogen peroxide employed is 1.73wt. % of the total amount of acrylic acid.

The colorless polyacrylate obtained has a specific viscosity of 0.41, adry matter content of 45.2% after neutralization to pH 8.6, and aresidual acrylic acid content of 24 ppm determined on the raw product bythe analytical method used in Experiment No. 1.

Experiment No. 4:

This experiment is carried out with the same apparatus and mode ofoperation as Experiment No. 1, but the concentration of acrylic acid inthe starting mixture and the amount of water are varied. The content ofthe monomer in the starting mixture is 26.5 wt. %, and the content ofsodium hypophosphite in the starting mixture is also 26.5 wt. %. heamount of the hydrogen peroxide added is 1.73 wt. % of the total amountof acrylic acid.

The colorless solution obtained is a polyacrylate having specificviscosity of 0.57, a dry matter content of 43.5% after neutralization topH 8.6 with sodium hydroxide of concentration 50%, and a residualacrylic acid content less than 10 ppm as determined by the analyticalmethod used in Experiment No. 1.

Experiment No. 5:

This experiment is carried out with the same apparatus, the same mode ofoperation, and the same quantities of reactants as in the precedingExperiment, with the exception that the amount of the hydrogen peroxideemployed is changed to 3.46 wt. % of the total amount of acrylic acid.

The polymer obtained is a colorless polyacrylate having a specificviscosity of 0.53, a dry matter content of 43.6% after neutralization topH 8.6 with sodium hydroxide of concentration 50%, and a residualacrylic acid content of 70 ppm determined with respect to the rawproduct according to the abovementioned HPLC method.

Experiment No. 6:

This experiment is carried out with the same apparatus, the same mode ofoperation, and the same quantities of reactants as in the precedingExperiment, with the exception that the amount of the hydrogen peroxideemployed is changed to 6.9 wt. % of the total amount of acrylic acid.

The colorless solution obtained is a polyacrylate having a specificviscosity 0.66, a dry matter content of 41.6% after neutralization to pH8.6 with sodium hydroxide of concentration 50%, and a residual acrylicacid content of 120 ppm determined on the raw product by the analyticalmethod used in the preceding Experiments.

Experiment No. 7:

This experiment is carried out with the same apparatus and mode ofoperation as in the preceding Experiment, but the “starting mixture” iscomprised of only water, and the amount of the hydrogen peroxideemployed was 3.46 wt. % of the amount of acrylic acid, which acrylicacid was added in parallel with said hydrogen peroxide.

The polymer produced is a colorless solution of polyacrylic acid havinga specific viscosity of 0.82, a dry matter content of 44.6% afterneutralization to pH 8.6 with sodium hydroxide of concentration 50%, anda residual acrylic acid content of 120 ppm determined on the rawproduct, according to the analytical method used in the precedingExperiments.

Experiment No. 8:

This experiment is carried out with the same apparatus as described inExperiment No. 7.

A starting mixture comprising 35 g sodium hypophosphite and 500 g wateris prepared at ambient temperature in a reactor.

Two charges to be introduced in parallel to the reactor with heating toreflux are also prepared which are a first beaker of 462 g 100% acrylicacid and a second beaker of 37 g of hydrogen peroxide. The contents ofthe beakers are charged, along with 63 g water, into the reactor.

The charges are added over a period of 2 hr, following which isobtained, a clear, colorless polyacrylic acid having a specificviscosity of 0.55.

After neutralization to pH 8.6 by adding sodium hydroxide ofconcentration 50%, the polyacrylate obtained has a dry matter content38.4% and a residual acrylic acid content of 190 ppm, on the rawproduct, according to the analytical method used in the precedingExperiments.

Experiment No. 9:

This experiment is identical to the preceding Experiment, except thatonly one fourth of the amount of sodium hypophosphite is charged to thereactor in the starting mixture. The polyacrylic acid obtained is clearand colorless, having a specific viscosity of 0.53.

After neutralization to pH 8.6 by adding sodium hydroxide ofconcentration 50%, the polyacrylate obtained has a dry matter content of38.4% and a residual acrylic acid content less than 10 ppm determined onthe raw product, according to the analytical method used in thepreceding Experiments.

Experiment No. 10:

This experiment was carried out with the same apparatus and the samegeneral method as used in the preceding Experiments. In the method, thefollowing components are combined:

a starting mixture in the reactor, comprising 130 g water, 30 g of 100%acrylic acid, 30 g of 50% sodium hydroxide, and a total amount of sodiumhypophosphite, corresponding to 0.024 g-atom phosphorus per mol acrylicacid; and

two charges introduced in parallel, the first comprising 467 g of 100%acrylic acid and the second comprising 10 g of hydrogen peroxide, plus190 g water.

The polyacrylate obtained is a clear, colorless polyacrylate having aspecific viscosity of 1.52.

After neutralization to pH 8.6 by adding sodium hydroxide at aconcentration of 50%, the polyacrylate obtained has a dry matter contentof 50.7% and a residual acrylic acid content less than 20 ppm determinedon the raw product, according to the analytical method used in thepreceding Experiments.

Experiment No. 11:

This experiment is carried out with the same apparatus and same generalmethod as used in the preceding Experiments. In the method, thefollowing components are combined:

a starting mixture in the reactor, comprising:

340 g water; and

one fourth of the total amount of sodium hypophosphite, the totalcorresponding to 0.012 g-atom phosphorus per mol acrylic acid; and

two charges introduced in parallel:

a first charge comprising 400 g 100% acrylic acid, 200 g water, and theremainder of the total amount of sodium hypophosphite, said totalcorresponding to 0.012 g-atom phosphorus per mol acrylic acid, and

a second charge comprising 3.3 g of hydrogen peroxide, plus 250 g water.

The polyacrylate obtained is a clear, colorless polyacrylate having aspecific viscosity of 2.4.

After neutralization to pH 8.6 by adding sodium hydroxide at aconcentration of 50%, the polyacrylate obtained has a dry matter contentof 38% and a residual acrylic acid content of 200 ppm determined on theraw product, according to the analytical method used in the precedingExperiments.

Experiment No. 12:

This experiment is carried out with the same apparatus and mode ofoperation as in the preceding Experiment, except that:

the total amount of sodium hypophosphite employed is 80% of thatemployed in the preceding Experiment; and

the amount of the hydrogen peroxide employed is twice the amountemployed in the preceding Experiment.

The polyacrylic acid obtained is a clear, colorless polyacrylic acidhaving a specific viscosity of 3.0.

After neutralization to pH 8.6 by adding sodium hydroxide at aconcentration of 50%, the polyacrylate obtained according to theinvention has a dry matter content of 38% and a residual acrylic acidcontent of 300 ppm determined on the raw product, according to theanalytical method used in the preceding Experiments.

Experiment No. 13:

This experiment is carried out with the same apparatus and mode ofoperation as in the preceding Experiment, except that:

the total amount of sodium hypophosphite employed is 0.0077 g-atomphosphorus per mol acrylic acid polymerized; and

the amount of the hydrogen peroxide employed is 78% of the amountemployed in Experiment 11.

The polyacrylic acid obtained is a clear, colorless polyacrylic acidhaving a specific viscosity of 4.8.

After neutralization to pH 8.6 by adding sodium hydroxide at aconcentration of 50%, the polyacrylate has a dry matter content of 38%and a residual acrylic acid content of 280 ppm determined on the rawproduct, according to the analytical method used in the precedingExperiments.

Experiment No. 14:

A starting mixture comprising of 600 g of water and one fourth of thetotal amount of hypophosphorous acid to be employed, said totalcorresponding to 0.09 g-atom phosphorus per mol acrylic acid to bepolymerized, is prepared, at ambient temperature, in a glass 2 L reactorhaving a stirrer, thermometer, and cooling means.

While the temperature in the starting mixture increases, the two chargesto be introduced in parallel over a period of 2 hr are prepared.

The first such charge introduced into a first beaker comprises 972 g of100% acrylic acid and the remaining three fourths of the total amount ofhypophosphorous acid, and the second charge introduced into a secondbeaker comprises 40 g of hydrogen peroxide, plus 120 g water.

The charges are added to the reactor gradually over a period of 2 hr at95° C., following which is obtained a polymer solution which is clearand colorless. The polymer is then completely neutralized to a pH of 8.6by adding sodium hydroxide of concentration 50%. The polyacrylate thusobtained is a homopolymer having a specific viscosity of 0.79 and a drymatter content of 46.6%. The residual content of acrylic acid in the rawproduct is less than 10 ppm, as determined by the above-described HPLCmethod.

EXAMPLE 2

The object of this Example is to illustrate an embodiment of theinvention in which homopolymers of maleic anhydride are prepared in theabsence of any metal or metal salt, particularly in the absence of persalts.

Experiment No. 15:

A starting mixture comprising 196 g of maleic anhydride, 288 g of 50%sodium hydroxide, 82 g of sodium hypophosphite, and 130 g water arecharged, at ambient temperature, to a glass 2 L reactor having astirrer, thermometer, and cooling means.

While the temperature in the starting mixture is increased to boiling, acharge comprising 10 g of hydrogen peroxide, plus 130 g water, isprepared. This charge is added to the reactor gradually over a period of2 hr, with the reactor contents being heated to boiling. Thereafter, apolymer solution is obtained which is clear and colorless.

The polymaleate is a clear, colorless polymaleate having a specificviscosity of 0.12, a dry matter content of 45.2% after neutralization topH 8.6 with sodium hydroxide of concentration 50%, and a residual maleicanhydride content of 90 ppm determined on the raw product according tothe analytical method used in the preceding Experiments.

Experiment No. 16:

This experiment is carried out with the same apparatus, the same mode ofoperation, and the same quantities of reactants as in Experiment 15,with the exception that the amount of the hydrogen peroxide added over aperiod of 2 hr is doubled.

The polymaleate obtained is clear and colorless, and has a specificviscosity of 0.16. After neutralization to pH 8.6 by adding sodiumhydroxide of 50% concentration, the product has a dry matter content of44.9% and a residual maleic anhydride content of 230 ppm determined onthe raw product, according to the analytical method used in thepreceding Experiments.

EXAMPLE 3

The object of this Example is to illustrate an embodiment of theinvention in which copolymers of acrylic acid and maleic acid areobtained with the use of hydrogen peroxide in the absence of any metalor metal salt.

Experiment No. 17:

A copolymer is obtained as follows: A starting mixture comprising 196 gof maleic anhydride, 288 g of 50% sodium hydroxide, 82 g of sodiumhypophosphite, and 130 g of water is charged, at ambient temperature, toa glass 2 L reactor having a stirrer, thermometer, and a cooling means.While the temperature in the starting mixture is increased, two chargesto be introduced in parallel over a period of 2 hr are prepared.

The first charge is comprised of 84 g of 100% acrylic acid, in a firstbeaker, and the second charge is comprised of 20 a of hydrogen peroxide,plus 130 g water, in a second beaker. The charges were added to thereactor gradually over a period of 2 hr, with the reactor contents beingheated to boiling, following which a polymer solution is obtained whichis completely clear and colorless.

The copolymer of the invention has a composition of monomer unitscorresponding to 30 wt. % acrylic acid and 70 wt. % maleic anhydride,and has a specific viscosity of 0.18. After neutralization to pH 8.6 byadding sodium hydroxide of concentration 50%, a dry matter content of52.2% is obtained. The residual content of maleic anhydride is 300 ppmdetermined on the raw product, according to the analytical method usedin the preceding Experiments. The corresponding figure for residualacrylic acid is 20 ppm.

Experiment No. 18:

The purpose of this Experiment is to illustrate a different monomerratio than in the preceding Experiment.

The starting mixture has the same reactants as in the precedingExperiment, and in the same amounts, except that the amount of sodiumhypophosphite is 18.38 wt. %, based on the total weight of the monomersplus the sodium hypophosphite. The two charges are introduced under thesame operating conditions and using the same apparatus as in ExperimentNo. 17. Here, as well, the first charge is comprised of acrylic acid ata concentration of 100%, and the second charge is comprised of hydrogenperoxide and water. However, here the amount of 100% acrylic acid issuch as to provide weight proportions of the monomers of 46 wt. %acrylic acid and 54 wt. % maleic anhydride. The amount of the second(hydrogen peroxide containing) charge remains the same as in ExperimentNo. 17.

The copolymer of the invention is obtained as a clear, colorlesssolution of 46 wt. % acrylic acid units, and 54 wt. % maleic anhydrideunits having a specific viscosity of 0.23. After neutralization to pH8.6 by adding sodium hydroxide of a concentration of 50%, the solutionhas a dry matter content of 50.8%, and a residual maleic anhydridecontent of 300 ppm determined on the raw product, according to theanalytical method used in the preceding Experiments. The correspondingfigure for residual acrylic acid is 30 ppm.

Experiment No. 19:

The purpose of this Experiment was to illustrate a different monomerratio.

The starting mixture has the same reactants as in the precedingExperiment, and in the same amounts, except that the amount of sodiumhypophosphite is 14.48 wt. % based on the total weight of the monomersplus the sodium hypophosphite. The two charges are introduced under thesame operating conditions using the same apparatus as in Experiment No.17. Here, as well, the first charge is comprised of acrylic acid at aconcentration of 100%, and the second charge is comprised of hydrogenperoxide and water. However, here the amount of 100% acrylic acid issuch as to provide weight proportions of the monomers of 60 wt. %acrylic acid and 40 wt. % maleic anhydride. The amount of the second(hydrogen peroxide containing) charge remains the same as in ExperimentNo. 17.

The copolymer of the invention is obtained as a clear, colorlesssolution of 60 wt. % acrylic acid units, and 40 wt. % maleic anhydrideunits having a specific viscosity of 0.31. After neutralization to pH8.6 by adding sodium hydroxide at a concentration of 50%, the solutionhas a dry matter content of 52.5%, and a residual maleic anhydridecontent of 207 ppm determined on the raw product, according to theanalytical method used in the preceding Experiments. The correspondingfigure for residual acrylic acid is 20 ppm.

Experiment No. 20:

The purpose of this Experiment is to illustrate a different monomerratio.

The starting mixture has the same reactants as in the precedingExperiment, and in the same amounts, except that the amount of sodiumhypophosphite is 12.5 wt. %, based on the total weight of the monomersplus the sodium hypophosphite. The two charges are introduced under thesame operating conditions using the same apparatus as in Experiment No.17. Here, as well, the first charge is comprised of acrylic acid at aconcentration of 100%, and the second charge is comprised of hydrogenperoxide and water. However, here the amount of 100% acrylic acid issuch as to provide weight proportions of the monomers of 66.7 wt. %acrylic acid and 33.3 wt. % maleic anhydride. The amount of the second(hydrogen peroxide containing) charge remains the same as in ExperimentNo. 17.

The copolymer of the invention is obtained as a clear, colorlesssolution of 66.7 wt. % acrylic acid units and 33.3 wt. % maleicanhydride units having a specific viscosity of 0.33. Afterneutralization to pH 8.6 by adding sodium hydroxide at a concentration50%, the solution has a dry matter content of 43.8%, and a residualmaleic anhydride content of 120 ppm determined on the raw product,according to the analytical method used in the preceding Experiments.The corresponding figure for residual acrylic acid is 50 ppm.

Experiment No. 21:

The purpose of this Experiment was to illustrate a different monomerratio.

The starting mixture has the same reactants as in the precedingExperiment, and in the same amounts, except that the amount of sodiumhypophosphite is 9.67 wt. %, based on the total weight of the monomersplus the sodium hypophosphite. The two charges are introduced under thesame operating conditions using the same apparatus as in Experiment No.17. Here, as well, the first charge is comprised of acrylic acid at aconcentration of 100%, and the second charge is comprised of hydrogenperoxide and water. However, here the amount of 100% acrylic acid issuch as to provide weight proportions of the monomers of 75 wt. %acrylic acid and 25 wt. % maleic anhydride. The amount of the second(hydrogen peroxide containing) charge remains the same as in ExperimentNo. 17.

The copolymer of the invention is obtained as a clear, colorlesssolution of 75 wt. % acrylic acid units and 25 wt. % maleic anhydrideunits having a specific viscosity of 0.46. After neutralization to pH8.6 by adding sodium hydroxide at a concentration of 50%, the solutionhas a dry matter content of 40.0%, and a residual maleic anhydridecontent of 95 ppm determined on the raw product, according to theanalytical method used in the preceding Experiments. The correspondingfigure for residual acrylic acid is 40 ppm.

Experiment No. 22:

The purpose of this Experiment is to illustrate a different monomerratio.

The starting mixture has the same reactants as in the precedingExperiment, and in the same amounts, except that the amount of sodiumhypophosphite is 7.24 wt. %, based on the total weight of the monomersplus the sodium hypophosphite. The two charges are introduced under thesame operating conditions using the same apparatus as in Experiment No.17. Here, as well, the first charge is comprised of acrylic acid at aconcentration of 100%, and the second charge is comprised of hydrogenperoxide and water. However, here the amount of 100% acrylic acid issuch as to provide weight proportions of the monomers of 83 wt. %acrylic acid and 17 wt. % maleic anhydride. The amount of the second(hydrogen peroxide containing) charge remained the same as in ExperimentNo. 17.

The copolymer of the invention is obtained as a clear, colorlesssolution of 83 wt. % acrylic acid units and 17 wt. % maleic anhydrideunits having a specific viscosity of 0.57. After neutralization to pH8.6 by adding sodium hydroxide at a concentration of 50%, the solutionhas a dry matter content of 41.8%, and a residual maleic anhydridecontent of 53 ppm determined on the raw product, according to theanalytical method used in the preceding Experiments. The correspondingfigure for residual acrylic acid is 52 ppm.

Experiment No. 23:

The purpose of this Experiment is to illustrate a different monomerratio.

The starting mixture has the same reactants as in the precedingExperiment, and in the same amounts, except that the amount of sodiumhypophosphite was 6.1 wt. %, based on the total weight of the monomersplus the sodium hypophosphite. The two charges are introduced under thesame operating conditions using the same apparatus as in Experiment No.17. Here, as well, the first charge is comprised of acrylic acid at aconcentration of 100%, and the second charge is comprised of hydrogenperoxide and water. However, here the amount of 100% acrylic acid issuch as to provide weight proportions of the monomers of 85 wt. %acrylic acid and 15 wt. % maleic anhydride. The amount of the second(hydrogen peroxide containing) charge remained the same as in ExperimentNo. 17.

The copolymer of the invention is obtained as a clear, colorlesssolution of 85 wt. % acrylic acid units and 15 wt. % maleic anhydrideunits having a specific viscosity of 0.77. After neutralization to pH8.6 by adding sodium hydroxide at a concentration of 50%, the solutionhas a dry matter content of 41.8%, and a residual maleic anhydridecontent of 60 ppm determined on the raw product, according to theanalytical method used in the preceding Experiments. The correspondingfigure for residual acrylic acid is 35 ppm.

Experiment No. 24:

The purpose of this Experiment is to illustrate a different monomerratio.

The starting mixture has the same reactants as in the precedingExperiment, and in the same amounts, except that the amount of sodiumhypophosphite is 5.77 wt. %, based on the total weight of the monomersplus the sodium hypophosphite. The two charges are introduced under thesame operating conditions and using the same apparatus as in ExperimentNo. 17. Here, as well, the first charge is comprised of acrylic acid ata concentration of 100%, and the second charge is comprised of hydrogenperoxide and water. However, here the amount of 100% acrylic acid issuch as to provide weight proportions of the monomers of 85.7 wt. %acrylic acid and 14.3 wt. % maleic anhydride. The amount of the second(hydrogen peroxide containing) charge remained the same as in ExperimentNo. 17.

The copolymer of the invention is obtained is as a clear, colorlesssolution of 85.7 wt. % acrylic acid units and 14.3 wt. % maleicanhydride units having a specific viscosity of 1.55. Afterneutralization to pH 8.6 by adding sodium hydroxide at a concentrationof 50%, the solution has a dry matter content of 47.4%, and a residualmaleic anhydride content of 70 ppm determined on the raw product,according to the analytical method used in the preceding Experiments.The corresponding figure for residual acrylic acid is 235 ppm.

Experiment No. 25:

The purpose of this Experiment is to illustrate a different monomerratio, and also a procedure wherein the amount of sodium hydroxide at aconcentration of 50% employed in the starting mixture was reduced by onehalf.

The starting mixture has the same reactants as in the precedingExperiment, and in the same amounts, except that:

the amount of sodium hypophosphite is 11.2 wt. %, based on the totalweight of the monomers plus the sodium hypophosphite, and

the amount of sodium hydroxide at a concentration of 50% employed in thestarting mixture is reduced by one half.

The two charges are introduced under the same operating conditions andusing the same apparatus as in Experiment No. 17. Here, as well, thefirst charge is comprised of acrylic acid at a concentration of 100%,and the second charge is comprised of hydrogen peroxide and water.However, here the amount of 100% acrylic acid is such as to provideweight proportions of the monomers of 70.6 wt. % acrylic acid and 29.4wt. % maleic anhydride. The amount of the second (hydrogen peroxidecontaining) charge remained the same as in Experiment No. 17.

The copolymer of the invention is obtained as a clear, colorlesssolution of 70.6 wt. % acrylic acid units and 29.4 wt. % maleicanhydride units having a specific viscosity of 0.39. Afterneutralization to pH 8.6 by adding sodium hydroxide at a concentrationof 50%, the solution has a dry matter content of 45%, and a residualmaleic anhydride content of 120 ppm determined on the raw product,according to the analytical method used in the preceding Experiments.The corresponding figure for residual acrylic acid is 110 ppm.

EXAMPLE 4

The object of this Example is to illustrate the possibility of varyingthe specific viscosity, for a copolymer of given monomeric composition.

Experiment No. 26:

The method used and the monomer composition employed are the same as inExperiment No. 23, but:

the amount (by weight) of sodium hypophosphite is increased by a factorof 1.5, one fourth of which amount is introduced in the starting mixtureand three fourths of which is introduced in the parallel addition ofcharges; and

the amount of the hydrogen peroxide is increased by a factor of 4.

The copolymer of the invention is obtained as a clear, colorlesssolution of 85 wt. % acrylic acid units and 15 wt. % maleic anhydrideunits having a specific viscosity of 0.44. After neutralization to pH8.6 by adding sodium hydroxide at a concentration of 50%, the solutionhas a dry matter content of 47.0%, and a residual maleic anhydridecontent of 10 ppm determined on the raw product, according to theanalytical method used in the preceding Experiments. The correspondingfigure for residual acrylic acid is also c. 10 ppm.

Experiment No. 27:

The method used and the monomer composition employed are the same as inthe preceding Experiment, but:

the amount (by weight) of sodium hypophosphite is reduced by a factor of3; and the amount of the hydrogen peroxide is reduced by a factor of 2.

The copolymer of the invention is obtained as a clear, colorlesssolution of 85 wt. % acrylic acid units and 15 wt. % maleic anhydrideunits having a specific viscosity of 1.26. After neutralization to pH8.6 by adding sodium hydroxide at a concentration of 50%, the solutionhas a dry matter content of 43.6%, and a residual maleic anhydridecontent of 140 ppm determined on the raw product, according to theanalytical method used in the preceding Experiments. The correspondingfigure for residual acrylic acid is also 140 ppm.

EXAMPLE 5

This Example illustrates the manufacture of other copolymers of theinvention.

Experiment No. 28:

An acrylic acid—methacrylic acid copolymer is produced by the samemethod as used in Experiment No. 17, with the addition of a chargecomprising acrylic acid and a charge comprising hydrogen peroxide pluswater, to a reactor containing water, methacrylic acid, sodiumhypophosphite, and a certain amount of 50% sodium hydroxide. Thecomponent amounts are adjusted such that the polymer obtained followingthe addition of reactants over a period of 2 hr under reflux is a clear,colorless copolymer of the invention having 13 wt. % methacrylic acidunits and 87 wt. % acrylic acid units and a specific viscosity of 0.84,a dry matter content of 50.4% after neutralization to pH 8.6 by addingsodium hydroxide at a concentration of 50%, and a residual methacrylicacid content of less than 10 ppm determined on the raw product,according to the analytical method used in the preceding Experiments.The corresponding figure for residual acrylic acid is also less than 10ppm.

Experiment No. 29:

To produce an acrylic acid—methacrylic acid copolymer, over a period of2 hr, under reflux, two charges are introduced to a reactor initiallycontaining 456 g water and 25% of the total amount of sodiumhypophosphite to be employed, which total amount corresponds to 0.064g-atom phosphorus per mol of monomers to be polymerized. One such chargecomprises 25 g of hydrogen peroxide, plus 75 g water. The other chargecomprises 300 g acrylic acid, 300 g methacrylic acid, and the remaining75% of the total amount of sodium hypophosphite to be employed.

The copolymer of the invention is obtained following the addition over aperiod of 2 hr under reflux as a clear, colorless copolymer of 50%acrylic acid and 50% methacrylic acid having a specific viscosity of1.0, a dry matter content of 38.6% after neutralization to pH 8.6 byadding sodium hydroxide at a concentration of 50%, and a residualacrylic acid content of 30 ppm determined on the raw product, accordingto the analytical method used in the preceding Experiments. Thecorresponding figure for residual methacrylic acid is less than 10 ppm.

Experiment No. 30:

A maleic anhydride—methacrylic acid copolymer is produced by the samemethod as used in Experiment No. 19, but the acrylic acid of ExperimentNo. 19 is replaced by methacrylic acid. The polymer obtained followingthe addition over a period of 2 hr under reflux is a clear, colorlesscopolymer of the invention having 60 wt. % methacrylic acid units and 40wt. % maleic anhydride units and having a specific viscosity of 0.32, adry matter content of 46.2% after neutralization to pH 8.6 by addingsodium hydroxide at a concentration of 50%, and a residual methacrylicacid content of 28 ppm determined on the raw product, according to theanalytical method used in the preceding Experiments. The correspondingfigure for residual maleic anhydride is 200 ppm.

Experiment 31:

This Experiment illustrates the production of an acrylic acid—acrylamidecopolymer.

A starting mixture comprises 200 g water and one fourth of the totalamount of sodium hypophosphite to be employed, said total correspondingto 0.059 g-atom phosphorus per mol of monomers to be polymerized. Themixture is prepared, at ambient temperature in a glass 2 L reactorhaving a stirrer, thermometer, and cooling means.

While the temperature of the starting mixture is increased, the twocharges to be introduced in parallel over a period of 2 hr are prepared.

The first charge comprises 181 g of 100% acrylic acid, 844 g ofacrylamide of 50% concentration, and the remaining three fourths of thetotal amount of sodium hypophosphite, which is placed in a first beaker.

The second charge comprises 25 g of hydrogen peroxide, mixed with anadditional 75 g water, the second charge being introduced into a secondbeaker.

These charges are added to the reactor gradually over a period of 2 hr,with the reactor contents being heated to boiling, following which apolymer in a solution is obtained which is clear and colorless.

The product obtained is a copolymer of the invention of 30 wt. % acrylicacid units and 70 wt. % acrylamide units having a specific viscosity of0.37, a dry matter content of 45.3% after neutralization to pH 8.6 byadding sodium hydroxide at a concentration of 50%, and a residualacrylic acid content of 30 ppm determined on the raw product, accordingto the analytical method used in the preceding Experiments. Thecorresponding figure for residual acrylamide is less than 10 ppm.

Experiment 32:

This Experiment illustrates an acrylic acid—sodium methallyl sulfonatecopolymer. A starting mixture, comprised of: 185 g water, the totalamount of sodium hypophosphite to be employed, corresponding to 0.045g-atom phosphorus per mol of monomers to be polymerized, and 145 g of100% sodium methallyl sulfonate (MTAS), is prepared, at ambienttemperature, in a glass 2 L reactor having a stirrer, thermometer, andcooling means.

While the temperature in the starting mixture is increased, the twocharges to be introduced in parallel over a period of 2 hr are prepared.

The first charge comprises 512 g of 100% acrylic acid, and is introducedinto a first beaker.

The second charge comprises 20 g of hydrogen peroxide, mixed with anadditional 180 g water, the second charge being introduced into a secondbeaker.

These charges are added to the reactor gradually over a period of 2 hr,with the reactor contents being heated to boiling, following which apolymer in a solution is obtained which is clear and colorless.

The product obtained is a copolymer of the invention of 78 wt. % acrylicacid units and 12 wt. % MTAS units having a specific viscosity of 1.19,a dry matter content of 51.5% after neutralization to pH 8.6 by addingsodium hydroxide at a concentration of 50%, and a residual acrylic acidcontent of less than 10 ppm determined on the raw product, according tothe analytical method used in the preceding Experiments. Thecorresponding figure for residual MTAS is also less than 10 ppm.

Experiment No. 33:

An acrylic acid—ethyl acrylate copolymer is produced with the sameapparatus and by the same method as used in Experiment No. 31, but the844 g of 50% acrylamide is replaced by 61 g of ethyl acrylate, and the181 g of 100% acrylic acid is replaced by 549 g of 100% acrylic acid.The product obtained is a copolymer of the invention of 90 wt. % acrylicacid units and 10 wt. % ethyl acrylate units having a specific viscosityof 0.59, a dry matter content of 46.7% after neutralization to pH 8.6 byadding sodium hydroxide at a concentration of 50%, and a residualacrylic acid content of less than 10 ppm determined on the raw product,according to the analytical method used in the preceding Experiments.The corresponding figure for residual ethyl acrylate is also less than10 ppm.

Experiment No. 34:

An acrylic acid—ethyl acrylate copolymer is produced with the sameapparatus and by the same method as used in Experiment No. 33, but theproportions of the amounts of the monomers are changed to 70 wt. %acrylic acid and 30 wt. % ethyl acrylate.

The product obtained is a copolymer of the invention of 70 wt. % acrylicacid units and 30 wt. % ethyl acrylate units having a specific viscosityof 0.61, a dry matter content of 50.6% after neutralization to pH 8.6 byadding sodium hydroxide at a concentration of 50%, and a residualacrylic acid content of 10 ppm determined on the raw product, accordingto the analytical method used in the preceding Experiments. Thecorresponding figure for residual ethyl acrylate is 15 ppm.

Experiment No. 35:

An acrylic acid—butyl acrylate copolymer is produced with the sameapparatus and by the same method as used in Experiment No. 33, but theethyl acrylate is replaced by an equal weight of butyl acrylate.

The product obtained is a copolymer of the invention of 90 wt. % acrylicacid units and 10 wt. % butyl acrylate units having a specific viscosityof 0.59, a dry matter content of 48.29% after neutralization to pH 8.6by adding sodium hydroxide at a concentration of 50%, and a residualacrylic acid content of less than 10 ppm determined on the raw product,according to the analytical method used in the preceding Experiments.The corresponding figure for residual ethyl acrylate is also less than10 ppm.

Experiment No. 36:

An acrylic acid—methyl methacrylate copolymer is produced with the sameapparatus and by the same method as used in the preceding Experiment,but the butyl acrylate is replaced by an equal weight of methylmethacrylate.

The product obtained was a copolymer of the invention of 90 wt. %acrylic acid units and 10 wt. % methyl methacrylate units having aspecific viscosity of 0.64, a dry matter content of 46.2% afterneutralization to pH 8.6 by adding sodium hydroxide at a concentrationof 50%, and a residual acrylic acid content of less than 10 ppmdetermined on the raw product, according to the analytical method usedin the preceding Experiments. The corresponding figure for residualmethyl methacrylate is also less than 10 ppm.

Experiment 37:

This Experiment illustrates production of an acrylicacid—acrylamide—ethylene glycol methacrylate phosphate terpolymer.

A starting mixture, comprised of 370 g water, and one fourth of thetotal amount of sodium hypophosphite to be employed, the totalcorresponding to 0.066 g-atom phosphorus per mol of monomers to bepolymerized, is prepared, at ambient temperature, in a glass 2 L reactorhaving a stirrer, thermometer, and cooling means.

While the temperature in the starting mixture is increased, the twocharges to be introduced in parallel over a period of 2 hr are prepared.

The first charge comprises 305 g of 100% acrylic acid, 99.6 g ofhydrolyzed ethylene glycol methacrylate phosphate, 260.6 g of 50%acrylamide, 100 g of water, and the remaining three fourths of the totalamount of sodium hypophosphite, which are introduced into a firstbeaker.

The second charge comprises 44 g of hydrogen peroxide, mixed with anadditional 66 g of water, the second charge being introduced into asecond beaker.

These charges are added to the reactor gradually over a period of 2 hr,with the reactor contents being heated to boiling, following which apolymer in a solution is obtained which is clear and colorless.

The product obtained is a copolymer of the invention of 57 wt. % acrylicacid units, 19 wt. % acrylamide units, and 24 wt. % ethylene glycolmethacrylate phosphate units having a specific viscosity of 0.48, a drymatter content of 41.9% after neutralization to pH 8.6 by adding sodiumhydroxide at a concentration of 50%, and a residual content of themonomers of less than 10 ppm determined on the raw product, according tothe analytical method used in the preceding Experiments.

Experiment No. 38:

An acrylic acid—acrylamide—ethylene glycol methacrylate phosphateterpolymer is produced with the same apparatus and by the same generalmethod as used in Experiment No. 37, but with less sodium hypophosphite.That is, the total amount of sodium hypophosphite employed in thepresent Experiment corresponds to 0.025 g-atom phosphorus per mol ofmonomers to be polymerized.

The product obtained is a copolymer of the invention of 57 wt. % acrylicacid units, 19 wt. % acrylamide units, and 24 wt. % ethylene glycolmethacrylate phosphate units having a specific viscosity of 1.0, a drymatter content of 43% after neutralization to pH 8.6 by adding sodiumhydroxide at a concentration of 50%, and a residual content of themonomers of less than 10 ppm determined on the raw product, according tothe analytical method used in the preceding Experiments.

EXAMPLE 6

This Example illustrates the use of polymers of the invention asdispersant(s) for mineral materials in aqueous media, particularly fordispersing kaolin in water.

In each of the following Experiments, 500 g kaolin is introduced into a1 L beaker containing 258 g water, 1.10 g (dry basis) of the dispersantbeing tested, and sufficient 50% sodium hydroxide to adjust the pH to C.7.2-7.5. The kaolin is introduced by gradual sprinkling into the mixtureunder agitation.

Experiment No. 39:

This Experiment was a control experiment in which no dispersant ispresent in the beaker.

Experiments 40 to 44:

In these Experiments, the invention is illustrated by using, asdispersants, the present copolymers prepared in Experiments Nos. 19, 21,22, and 23, and the present homopolymer prepared in Experiment No. 9,with each dispersant being neutralized to pH 8.6 by adding sufficientsodium hydroxide at a concentration of 50%. After agitation for 45 min,the Brookfield viscosities are measured at ambient temperature, with theaid of a Brookfield type RVT viscometer at 100 rpm.

The results of the measurements of the Brookfield viscosity of theaqueous suspensions of kaolin are presented in Table 1.

TABLE 1 Dispersant Used Amount of Type of Dispersant Used Dry MatterBrookfield Experiment Dispersant (Wt. % Dry in the Viscosities No. UsedBasis/dry Basis Slurry (%) (mPa-sec) Control 39 — 0 66.0 >100,000Invention 40 Copolymer 0.22 66.4 500 of Exp. 19 Invention 41 Copolymer0.22 66.2 650 of Exp. 21 Invention 42 Copolymer 0.22 66.0 745 of Exp. 22Invention 43 Copolymer 0.22 66.0 1220 of Exp. 23 Invention 44 Copolymer0.22 66.0 410 of Exp. 9

It can be seen from Table 1 that the present copolymers can be used toprovide aqueous dispersions of kaolin which are industrially useful,thus demonstrating the suitability of the copolymers as dispersants formineral materials.

EXAMPLE 7

This Example illustrates the use of polymers of the invention, producedby the present method, as dispersant(s) for mineral materials in aqueousmedia for use in the paper industry, particularly for dispersing calciumcarbonate in water.

In each of the Experiments 45 to 48, using the same method as in thepreceding Example, calcium carbonate of a particle size distributionsuch that 75% of the particles have diameters less than 1 micron areemployed in an amount such that the dry matter concentration achieved is72%, and the given dispersant is employed in the amount of 0.75 wt. %dry basis dry basis, based on the weight of the calcium carbonate.

In each of the Experiments, a different dispersant is tested.

Experiment No. 45:

This Experiment is a control experiment in which no dispersant ispresent in the beaker.

Experiments 46 to 48:

In these Experiments, the invention is illustrated by using asdispersants the present copolymers prepared in Experiments Nos. 24, 23,and 22, with each dispersant being neutralized to pH 8.6 by addingsufficient sodium hydroxide at a concentration of 50%.

After agitation for 45 min, the Brookfield viscosities are measured atambient temperature, with the aid of a Brookfield type RVT viscometer at10 rpm and 100 rpm.

The results of the measurements of the Brookfield viscosity of theaqueous suspensions of calcium carbonate are presented in Table 2.

TABLE 2 Dispersant Used Amount of Type of Dispersant Used Dry MatterBrookfield Experiment Dispersant (wt. %, dry in the Slurry ViscositiesNo. Used basis/dry Basis (wt. %) (mPa.s) Control 45 — 072 >100,000 >100,000 Invention 46 Copolymer 0.75 72 650 310 of Exp. 24Invention 47 Copolymer 0.75 72 5500 955 of Exp. 23 Invention 48Copolymer 0.75 72 19000 2100 of Exp. 22

Similarly, in Experiments Nos. 49 to 54, using the same method as in thepreceding Example, precipitated calcium carbonate supplied by the firmSolvay under the tradename “Socal P3” is employed in an amount such thatthe dry matter concentration achieved is 70%, and the given dispersantis employed in the amount of 0.7 wt. %, dry basis/dry basis, based onthe weight of the calcium carbonate.

In each of the Experiments, a different dispersant is tested.

Experiment No. 49:

This Experiment is a control experiment in which no dispersant ispresent in the beaker.

Experiments 50 to 54:

In these Experiments, the invention is illustrated by using asdispersants the present copolymers prepared in Experiments Nos. 21 to24, and the inventive homopolymer prepared in Experiment No. 9, witheach dispersant being neutralized to pH 8.6 by adding sufficient sodiumhydroxide at a concentration of 50%.

After agitation for 45 min, the Brookfield viscosities are measured atambient temperature, with the aid of a Brookfield type RVT viscometer at100 rpm.

The results of the measurements of the Brookfield viscosity of theaqueous suspensions of “Socal P3” are presented in Table 3.

TABLE 3 Dispersant Amount of dispersant used Dry Matter BrookfieldExperiment (wt. %, dry in the viscosities No. Type basis/dry basisSlurry (%) (mPa-sec) Control 49 — 0 70 >100,000 Invention 50 Copolymer0.7 70 920 of Exp. 21 Invention 51 Copolymer 0.7 70 870 of Exp. 22Invention 52 Copolymer 0.7 70 720 of Exp. 23 Invention 53 Copolymer 0.770 580 of Exp. 24 Invention 54 Copolymer 0.7 70 760 of Exp. 9

Tables 2 and 3 show the effectiveness of the present copolymers asdispersants for mineral materials.

EXAMPLE 8

This Example relates to a preparation of a suspension of calciumcarbonate of relatively large particle size which is comminuted to forma microparticulate suspension.

Various coarse calcium carbonate suspensions are prepared from naturalcalcium carbonate of mean particle size 50 micron, as follows:

For Experiment No. 55 (control experiment): Simple 25% suspension inwater, with no dispersant added.

For Experiment No. 56 (invention): The polyacrylate from Experiment No.5, completely neutralized with sodium hydroxide and magnesium hydroxidein a ratio corresponding to a neutralization of 50% sodium—50%magnesium, is added as a dispersant.

For Experiment No. 57 (invention): The polyacrylic acid from ExperimentNo. 9, completely neutralized with sodium hydroxide and magnesiumhydroxide in a ratio corresponding to a neutralization of 50% sodium—50%magnesium, is added as a dispersant.

For Experiment No. 58 (invention): The polyacrylic acid from ExperimentNo. 5, completely neutralized with sodium hydroxide and calciumhydroxide in a ratio corresponding to a neutralization of 70% sodium—30%calcium, is added as a dispersant.

For Experiment No. 59 (invention): The polyacrylic acid from ExperimentNo. 9, completely neutralized with sodium hydroxide and calciumhydroxide in a ratio corresponding to a neutralization of 70% sodium—30%calcium, is added as a dispersant.

For each Experiment, an aqueous suspension of calcium carbonate from theOrgon deposit in France is prepared which has a particle sizes less than10 micron.

The aqueous suspension has a dry matter content 76 wt. %, based on thetotal weight of the suspensions, with the exception of the controlsuspension which has a dry matter content of 25 wt. %.

The milling agent is introduced into the suspension in the amountindicated in Table 4 which are units of wt. %, based on dry weight ofthe milling agent per dry weight of the calcium carbonate beingcomminuted.

The suspension is circulated in a comminuting mill of type “Dyno-Mill”with a fixed cylinder and rotating rotor, wherein the comminuting bodiescomprise Corundum spheres of diameters in the range of 0.6 mm to 1.0 mm.

The total volume occupied by the comminuting bodies is 1,150 cc, and thetotal weight of the comminuting bodies is 2,900 g.

The mill chamber has a volume of 1,400 cc.

The circumferential speed of the mill is 10 m/sec.

The suspension of calcium carbonate is recycled at 18 L/hr.

The outlet of the “Dyno-Mill” mill is equipped with a separator of mesh200 micron, which permits removal of the comminuting bodies from thesuspension resulting from the milling.

During each milling run, the temperature is maintained at c. 60° C.

At the end of the milling run (time To), a sample of the pigmentsuspension having 80% of the particles of particle size less than 1micron is recovered in a flask. The viscosity of this sample is measuredwith a Brookfield type RVT viscometer, at 20° C. and speeds 10 rpm and100 rpm, with a suitable rotor. This provided the “viscosity at To”.

After the suspension is allowed to settle in the flask for 8 da, asuitable rotor for a Brookfield type RVT viscometer is introduced intothe quiescent contents in the flask, and the viscosity of the suspensionis measured again, at 20° C. and speeds 10 rpm and 100 rpm. Thisprovides the “viscosity prior to agitation”.

The flask is then agitated, following which the viscosity is measured athird time by the same means. This provides the “viscosity followingagitation”.

All of these experimental results are shown in Table 4.

TABLE 4 Concentration Milling Agent Brookfield Viscosity of theSuspension (at of the Consumption 20° C. in mPa·s) Suspension of Milling8 Days AVAG 8 Days APAG Experiment (dry matter) Specific agent (wt. % To10 T/min- 10 T/min- 10 T/min- No. [wt. %] viscosity (dry/dry)) 100 T/min100 T/min 100 T/min Control 55 25 — —  800-450 20,000-2500  1200-650 Invention 56 76 0.53 0.98 1080-330 2060-620 820-280 Invention 57 76 0.531.10  950-290 1400-450 900-275 Invention 58 76 0.53 0.95 1030-330 7600-1300 930-320 Invention 59 76 0.53 0.99 1930-570 10,000-1660 1400-450  AVAG: Measured viscosity before agitation of the suspensionAPAG: Measured viscosity after agitation of the suspension

It can be seen from Table 4 that the present polymers are effective asmilling agents for aqueous suspensions of mineral materials whichsuspensions have high dry matter concentrations.

EXAMPLE 9

This Example shows the use of various polymers of the invention in flat(matt) water-based interior paints. The effectiveness of the polymers asdispersants and their ability to increase the water-resistance of thedried film are tested, by way of evaluating the Theological stabilityand water-resistance of the various flat interior paints prepared.

In each Experiment, other than the Control, 160 g water and 1 g 28%ammonium hydroxide are added to a vessel in which is added 0.06 wt. % ofthe dispersant being tested on a dry basis, based on the total weight ofthe given flat water-based paint formulation.

After several seconds of agitation following the introduction of thedispersant copolymer into the aqueous ammonium hydroxide, the othercomponents of the flat water-based paint formulation are added insuccession, as follows:

2 g “MERGAL K6N”, a biocide sold commercially by the firm Riedel deHaen;

1 g “BYK 03411, a defoamant sold commercially by the firm Byk;

41 g “RL 68”, a rutile (titanium dioxide) sold commercially by the firmThann et Mulhouse;

327.9 g “DURCAL 2”, a natural calcium carbonate sold commercially by thefirm Omya;

215.2 g “HYDROCARB”, a natural calcium carbonate sold commercially bythe firm Omya;

82 g “RHODOPAS DS 910”, a styrene-acrylic binder in the form of adispersion, sold commercially by the firm Rhone-Poulenc;

10.2 g monoethylene glycol;

10.2 g white spirits of petroleum;

1.3 g 28% ammonium hydroxide;

13.6 g “VISCOATEX 46”, a thickener sold commercially by the firm Coatex;and sufficient water to provide a total formulation weight of 1000 g.

Various dispersants are tested, as follows:

Experiment No. 60:

This Experiment is a control experiment, in which no dispersants areused.

Experiments Nos. 61 to 64:

In these Experiments, which illustrate the invention, the copolymersfrom Experiments Nos. 17, 19, 20, and 23, respectively, are employed.

For each Experiment, the aqueous formulation is agitated for severalminutes, following which the Brookfield viscosity is measured at 25° C.with a type RVT Brookfield viscometer equipped with a suitable rotor, at10 rpm.

The rheological stabilities of the formulations over time, and withelevated temperature, are determined by measurement of the Brookfieldviscosities (25° C., 10 rpm) of the formulations after storage atambient temperature without agitation for 24 hr; then after storage 1 wkin a heated cabinet at 50° C.; and then after storage 1 mo in the samecabinet at 50° C.

In the course of preparing the formulations for the Experiments, thedimension of the vortex present around the stirring axis is evaluatedvisually during the entire period of addition of the charges and/ormineral pigments, and the various additives, with the aim of estimatingthe ease of mixing of the formulation. Such ease of mixing is anindication (or aspect) of the effectiveness of the dispersant agent.

In Table 5, infra, in which all of the results obtained for thedifferent Experiments are reported, the following codes are used for theobservations relating to “ease of mixing”:

TB (very good): The vortex is of constant dimension and shape during theentire incorporation of the charges and/or mineral pigments; thisindicates excellent fluidity of the resulting composition.

B (good): The dimension of the vortex decreases slightly during theincorporation of the charges and/or mineral pigments.

AB (adequate): The dimension of the vortex change appreciably during theincorporation of the charges and/or mineral pigments; nonetheless it ispossible to achieve thorough intermixing of the various components ofthe formulation.

M (poor): For the Control experiment, this indicates that the vortexaround the stirring axis completely disappeared, resulting in poormixing of the medium.

After the Theological behavior of the various flat interior paints ismeasured, the resistance to abrasion of the dried films under wetconditions is tested by the German standard DIN 53778 Part 2, for eachof the Experiments.

In this test, carried out with a Gardner model “M 105-A” abrasimeter(conforming to DIN 53778), the number of revolutions made by a brushcalibrated according to DIN 53778 in abrading a previously dried film ofthe paint to a depth of 100 micron is measured. The sample is preparedby drying the film on a “LENETA” board. The test is conducted in thepresence of a detergent solution, to test complete abrasion of the paintfilm.

The results are presented in Table 5.

TABLE 5 Brookfield Viscosity of the Paint Formulation Abrasionresistance Dispersant (mPa-sec) while wet Experiment (dry) At time Attime T = 1 wk At time T = 1 mo. Ease of according No. (wt. %) At Time T= 0 T = 24 hr. at 50° C. at 50° C. mixing to DIN 53778 Control 60 021,000 34,000 66,000 68,000 M 500 Invention 61 0.06 17,500 15,500 47,00058,000 AB 660 62 0.06 16,500 11,000 34,000 44,000 B 750 63 0.06 17,00014,000 32,000 38,000 TB 750 64 0.06 16,500 14,500 22,000 30,000 TB 750

From Table 5 it may be concluded that the flat water-based interiorpaints containing the polymers of the invention provide:

good rheologic stability (Brookfield viscosity at 10 rpm at 25° C. after1 mo storage at 50° C. is less than 60,000 mPa-sec); and

ease of mixing rated at least adequate to good (“AB”); whereas thecontrol formulation without a dispersant does not provide thesebenefits. Further, the abrasion resistance under wet conditions isappreciably greater with the present formulations than with the controlformulation.

EXAMPLE 10

This Example illustrates the use of polymers of the invention asanti-scaling agent(s) in water treatment. Measurements are made of theretardation of precipitation of alkaline earth ions, particularlyprecipitation of the calcium carbonate present in natural and artificialwaters of varying salt content, in the presence of the polymers.

In each Experiment, municipal tap water containing 5 ppm of one of thepolymers being tested is added to a 1 L flask equipped with coolingmeans, which includes a reflux condenser, except that in Experiment No.65 and the Control experiment, the tap water used did not contain anypolymer.

Experiments Nos. 66 and 67 illustrate the invention with the use of thecopolymers of Experiments Nos. 21 and 20, respectively.

The water charge as described is heated to boiling, under reflux. Attime t=0, defined as the time at which the first ring of bubblesappeared (onset of boiling), a sample of volume 20 mL is taken. Thewater is then immediately filtered through a 0.45 micron “Millipore”filter, and the filtrate is transferred to a 100 mL beaker to betitrated with EDTA. The beaker had previously been charged with 3 mL ofa concentrated ammoniacal indicator buffer, “Merck 108430”, which isstirred in the beaker with the aid of a magnet bar stirrer. The mixtureis agitated for several seconds, and then 5.10-3 M EDTA is addedgradually from a burette, until the mixture turned a strong green color.The water hardness determined (hydrotimetric titer, “HT”), in units ofFrench degrees of hardness (1 French degree=10 mg of CaCO₃ equivalentper liter of water) is given as follows:

HT (° French)=Volume of EDTA added×2.5. The value for HT determined atthis point is designated “HT 0”. Corresponding additional samples aretaken after 15 minutes of boiling (t=15 min) and 30 minutes of boiling(t=30 min). The values for HT determined are designated “HT 15” and “HT30”, respectively. The data are reported in Table 6.

TABLE 6 Anti- Hydrotimetric Hydrotimetric Hydrotimetric Experimentscaling titre at time titre at time titre at time No. Agent t = 0 min t= 15 min t = 30 min Control 65 — 29.4 7.9 6.6 Invention 66 Copolymer29.4 19.85 14.8 of Exp. 21 Invention 67 Copolymer 29.4 23.4 19.3 of Exp.20

It is seen from Table 6 that the present polymers are effective asanti-scaling agents.

EXAMPLE 11

This Example relates to alkaline chlorinated formulations used, interalia, as bleaching agents and disinfectants in detergent applications.The Example may also relate to other bleaching formulations commonlyfound in detergent practice.

In particular, the Example illustrates the use of the present polymersas anti-scaling agents and dispersants in such formulations, wherein itis shown that the presence of the polymers does not detract from thestability of alkaline. chlorinated compositions, and does not promote adecrease in the chlorometric index, which would indicate a loss ofeffectiveness of the sodium hypochlorite solution contained in thedetergent composition.

For each Experiment, a mixture comprising 50.65 g water, 29.35 g Javellewater of chlorometric index 36.96° Cl (see definition, infra), and 15 g50% sodium hydroxide is prepared, in a 200 mL beaker, under agitation.

Once this mixture is thoroughly intermixed, 5 g of the polymer to betested in situ is added, under agitation, except that in Experiment No.65, the control experiment, no polymer is added.

After the resulting mixture is cooled, 10 mL of this mixture is added to100 mL water.

After thus diluting the mixture, a 20 mL sample of the dilutedchlorine-containing alkaline composition is taken and is subjected toanalysis to determine the hypochlorite present.

The analysis is by the Bunsen method based on oxidation of iodide ionsby hypochlorite ions, to generate iodine, which is titrated with 0.1 Nsodium thiosulfate solution. The chlorometric index, “° Cl”, of thechlorine-containing alkaline composition, is then calculated from thetiter.

For the 20 mL sample referred to, the chlorometric index is given by:${{^\circ}Cl}\quad = {\frac{\text{Volume~~~of~~~sodium~~~thiosulfate}}{20} \times 11.2}$

The value of the chlorometric index obtained in Experiment No. 68(Control experiment) is then taken as a reference value, to represent100% of the hypochlorite present in the formulation.

The various Experiments are as follows:

Experiment No. 68:

Control experiment. No polymer used.

Experiment No. 69:

Experiment illustrating the prior art, using a sodium polyacrylateproduced according to a prior art method and having a specific viscosityof 0.56.

Experiment No. 70:

Experiment illustrating the invention, using the polyacrylic acid fromExperiment No. 9, completely neutralized with sodium hydroxide.

For each of these Experiments, the chlorometric index (° Cl) isdetermined by the same method, after 24 hr and after 8 da.

The results presented in Table 7 are in terms of “percent ofhypochlorite remaining, based on the Control”.

TABLE 7 Experiment To 24 hours 8 Days No. Polymer (%) (%) (%) Control 68— 100 100 100 State of 69 Polyacrylate 100 98.4 90.6 the Art (Na salt)specific μ = 0.56 Invention 70 Polyacrylate 100 100 94.9 of Exp. 9

Table 7 reveals the changes in the chlorometric index for each of thesolutions, illustrating that the present polymers do not destabilize thechlorometric index of the chlorine-containing alkali composition.

EXAMPLE 12

This Example relates to the use of polymers of the invention asfluidifying agent(s) for drilling muds and the like, wherein the aqueousphase is based on fresh (non-saline) water.

A drilling mud is prepared as follows:

500 cc fresh water is charged to a 5 L beaker, equipped with a Rayneriturbine stirrer of diameter 50 mm operated at 2000 rpm.

Then 3 g technical Na₂CO₃ is added rapidly under agitation, toprecipitate Ca²⁺ and Mg²⁺ ions.

Then, continuing agitation, 75 g of a bentonite (A) (yield 20-25 cum/ton metric, measured according to the standard OCMADFCP4-1973) isadded to the mixture over a period of 15 min.

Thereafter, continuing agitation, 112.5 g of an attapulgite, (B) (yield30-35 cu m/ton metric, measured according to the standardOCMA-DFCP1-1973) was added to the mixture over a period of 15 min.

Subsequently, still continuing agitation, 37.5 g of technicalcarboxymethylcellulose (low-viscosity, according to standardOCMA-DFCP2-1980) is added to the mixture over a period of 15 min.

Then, continuing agitation, 225 g of an argile, (C) of low swellingindex (yield c. 15 cu m/ton metric) is added over a period of 20 min.

Following this, the pH of the medium is measured and is adjusted to avalue in the range 9.5-10 by adding sodium hydroxide solution.

The resulting drilling mud is subjected to shearing action by means of aSylverson Type L.R2 agitator provided with a high-shear grille ofdiameter 35 mm.

The drilling mud is then allowed to rest 24 hr, followed by agitation bythe above-mentioned Rayneri turbine stirrer for c. 5 minutes.

Thereafter, two samples of 500 cc each are taken, to test theeffectiveness of fluidifying agents of the invention.

Experiment No. 71 is a Comparison experiment, wherein there is added tothe above-described drilling mud 7.5 g of a sodium polyacrylate of aspecific viscosity of 0.4, which material is regarded as the bestfluidifying agent known to the art.

Experiment No. 72 is a representative experiment of the invention,wherein there is added to the above-described drilling mud, as an activeagent, 7.5 g of the sodium polyacrylate from Experiment No. 3, having aspecific viscosity of 0.41.

The mixture for each of these Experiments is mixed 10 min with aHamilton Beach mixer (“low” position), while maintaining the pH in therange of 9.5-10.

Following this mixing, the rheological characteristics at 20° C. aremeasured with a “FANN 35” viscometer; and the API characteristics of thefiltrate are measured at a pressure of 100 psi over a period of 30 min,by the method familiar to persons skilled in the art.

The rheological characteristics measured are the apparent viscosity(“Va”), plastic viscosity (“Vp”), yield value (“Yv”), the gel at 0 andthe gel at 10. These parameters are defined in the publication “Manualof Rheology of Drilling Muds and Slag Cements” (in French), 1979, pub.Edition Technip. All of these characteristics are reported in Table 8.

TABLE 8 State of the Art Invention Experiment No. 71 72 pH 9.51 9.50LECLT 600 T 87 88 LECT 300 T 64 65 Va 43.5 44 Vp 23 23 Yv 41 42 Gel 0 4042 Gel 10 250 255

It can be seen from Table 8 that the mud containing the polyacrylate ofthe invention has Theological characteristics equivalent to those of themud containing a polyacrylate known to the art.

EXAMPLE 13

This Example relates to the use of polymers of the invention in ceramicstechnology.

A dispersion comprising a slip is prepared. For Experiment No. 73, asodium polyacrylate of a specific viscosity of 0.4 known to the art isemployed. For Experiment No. 74 the sodium polyacrylate from ExperimentNo. 3 of the invention is employed.

For each of these Experiments, the following are added to 1088.8 gwater, under agitation:

1.645 g (dry weight) of the polymer being tested;

3.422 g sodium silicate; and

1.324 g sodium carbonate.

After the mixture is thoroughly mixed, 2800 g of an argile comprisedessentially of argiles, feldspars, and sands is added.

After agitating for 1 hr, the Brookfield viscosities are measured with aBrookfield type “RVT” viscometer, at 1 rpm, 10 rpm, and 100 rpm.

The results obtained are presented in Table 9.

TABLE 9 State of the Art Invention Experiment No. 73 74 Viscosity at 1 1 T/mn 4400 4350 rpm (mPa-sec)  10 T/mn 1700 1600 100 T/mn 1600 1500

It can be seen from Table 9 that the slip containing the polyacrylate ofthe invention has rheological characteristics equivalent to those of theslip containing a polyacrylate known to the art.

EXAMPLE 14

This Example relates to the use of polymers of the invention as waterretention agent(s) in the papermaking industry.

For each Experiment, a coating slip having a dry matter content of 68%is prepared which contains the water retention agent being tested in theamount of 0.3 wt. % (dry basis) based on the dry weight of the calciumcarbonate component.

For Experiment No. 75, the water retention agent is a sodiumpolyacrylate known to the art, having a specific viscosity of 5.0. ForExperiment No. 76, illustrating the invention, the water retention agentis the inventive sodium polyacrylate from Experiment No. 13, having aspecific viscosity of 4.8.

For each Experiment, the coating slip is prepared by adding to a 1000 mLbeaker:

an amount of water necessary to provide a final concentration of theslip of 68%; and

an amount of a suspension of calcium carbonate of particle sizedistribution such that 90% of the particles have a particle size lessthan 2 micron providing 500 g of calcium carbonate on a dry weightbasis.

After this suspension is formed, the given water retention agent isintroduced, under agitation.

After agitating 15 min, a quantity of latex (“Acronal S 360 D”, suppliedby BASF) corresponding to 10.5 wt. % (dry weight of latex divided by dryweight of calcium carbonate) is added. After an additional 15 min ofagitation, the Brookfield viscosities are measured at 10 rpm and 100 rpmat ambient temperature, using a Brookfield type “RVT” viscometerequipped with a no. 3 rotor.

To test water retention, the coating slip is subjected to a pressure of100 psi (7 bar) in an API filter press having a permeable surface.

This filter press is comprised essentially of a bracket with a clampingscrew which enables the three parts of the filter body to be heldtogether, which three parts are namely:

a base piece having an orifice and equipped with a delivery tube throughwhich the filtrate exits, wherein the base piece supports a 60×80 meshmetal screen on which a filter paper 90 mm in diameter is placed (Fannreference N 87000100 Box, supplied by Fann Instrument Company);

a cylinder of 76.2 mm interior diameter and 128 mm height; and

a cover provided with an inlet for compressed gas, and having a flatgasket to provide a seal between the cover and the cylinder, wherein thegasket is of the same type as those used on the base piece.

After 20 min under pressure in the filter, the volume of water collectedin a graduated cylinder or the like disposed below the filter body ismeasured. The lower this volume, the better the water retention.

The results are presented in Table 10.

TABLE 10 Volume Viscosity Viscosity collected Experiment at 10 rpm at100 rpm in 20 min. No. (mPa-sec) (mPa-sec) (mL) State of 75 5200 890 3.5the art Invention 76 5000 800 3.2

It can be seen from Table 10 that a polymer of the invention may be usedas a retention agent in the papermaking industry.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is,therefore, to be understood that within the scope of the appendedclaims, the invention may be practiced otherwise than as specificallydescribed herein.

French priority Application No. 96 09345 filed Jul. 19, 1996 is herebyincorporated by reference.

What is claimed as new and desired to be secured By Letters Patent ofthe United States is:
 1. A method of dispersing a mineral material in anaqueous medium, by employing a polymer in said aqueous solution as amilling agent and/or dispersant; wherein said polymer is obtained by amethod of manufacturing homopolymers and/or copolymers, comprising:polymerizing ethylenically monounsaturated monomer(s) in an aqueoussolution in a reaction vessel containing compounds which contain aphosphorus atom of degree of oxidation less than 5, said phosphorouscompounds being introduced in amounts of 0.005-0.49 gram-atom phosphorusper mol of unsaturation in said ethylenically unsaturated monomer(s) inthe presence of hydrogen peroxide and in the absence of any agent(s)which decomposes hydrogen peroxide thereby forming free radicals, in theabsence of any other generator of free radicals, and in the absence ofany per salt and/or any other transfer agent; wherein for each monomer,the residual monomer concentration is less than or equal to 300 ppm,based on the weight of the raw product, wherein the dry matter contentis at least 38; and wherein these constraints apply regardless of themonomer composition.
 2. A method of retaining water in papermaking,comprising: achieving water retention agent in papermaking with anaqueous solution of a polymer obtained by a method of manufacturinghomopolymers and/or copolymers, comprising: polymerizing ethylenicallymonounsaturated monomer(s) in an aqueous solution in a reaction vesselcontaining compounds which contain a phosphorus atom of degree ofoxidation less than 5, said phosphorous compounds being introduced inamounts of 0.005-0.49 gram-atom phosphorus per mol of unsaturation insaid ethylenically unsaturated monomer(s) in the presence of hydrogenperoxide and in the absence of any agent(s) which decomposes hydrogenperoxide thereby forming free radicals, in the absence of any othergenerator of free radicals, and in the absence of any per salt and/orany other transfer agent; wherein for each monomer, the residual monomerconcentration is less than or equal to 300 ppm, based on the weight ofthe raw product; wherein the dry matter content is at least 38%; andwherein these constraints apply regardless of the monomer composition.3. A method of treating industrial and/or household water, by adding tosaid industrial or household water a polymer which functions as asequestering agent, a precipitation inhibitor, or an inhibitor ofmineral incrustation; wherein said polymer is obtained by a method ofmanufacturing homopolymers and/or copolymers, comprising: polymerizingethylenically monounsaturated monomer(s) in an aqueous solution in areaction vessel containing compounds which contain a phosphorus atom ofdegree of oxidation less than 5, said phosphorous compounds beingintroduced in amounts of 0.005-0.49 gram-atom phosphorus per mol ofunsaturation in said ethylenically unsaturated monomer(s) in thepresence of hydrogen peroxide and in the absence of any agent(s) whichdecomposes hydrogen peroxide thereby forming free radicals, in theabsence of any other generator of free radicals, and in the absence ofany per salt and/or any other transfer agent; wherein for each monomer,the residual monomer concentration is less than or equal to 300 ppm,based on the weight of the raw product; wherein the dry matter contentis at least 38; and wherein these constraints apply regardless of themonomer composition.
 4. A method of conducting reverse osmosis or ultrafiltration, comprising: employing a polymer in aqueous solution as ananti-scaling or anti-corrosion agent; wherein said polymer is obtainedby a method of manufacturing homopolymers and/or copolymers, comprising:polymerizing ethylenically monounsaturated monomer(s) in an aqueoussolution in a reaction vessel containing compounds which contain aphosphorus atom of degree of oxidation less than 5, said phosphorouscompounds being introduced in amounts of 0.005-0.49 gram-atom phosphorusper mol of unsaturation in said ethylenically unsaturated monomer(s) inthe presence of hydrogen peroxide and in the absence of any agent(s)which decomposes hydrogen peroxide thereby forming free radicals, in theabsence of any other generator of free radicals, and in the absence ofany per salt and/or any other transfer agent; wherein for each monomer,the residual monomer concentration is less than or equal to 300 ppm,based on the weight of the raw product; wherein the dry matter contentis at least 38; and wherein these constraints apply regardless of themonomer composition.
 5. A method of drilling, comprising: drilling theearth by employing a polymer in a drilling medium as a fluidifyingagent; wherein said polymer is obtained by a method of manufacturinghomopolymers and/or copolymers, comprising: polymerizing ethylenicallymonounsaturated monomer(s) in an aqueous solution in a reaction vesselcontaining compounds which contain a phosphorus atom of degree ofoxidation less than 5, said phosphorous compounds being introduced inamounts of 0.005-0.49 gram-atom phosphorus per mol of unsaturation insaid ethylenically unsaturated monomer(s) in the presence of hydrogenperoxide and in the absence of any agent(s) which decomposes hydrogenperoxide thereby forming free radicals, in the absence of any othergenerator of free radicals, and in the absence of any per salt and/orany other transfer agent; wherein for each monomer, the residual monomerconcentration is less than or equal to 300 ppm, based on the weight ofthe raw product; wherein the dry matter content is at least 38; andwherein these constraints apply regardless of the monomer composition.6. A method of cleaning, comprising: conducting the cleaning in anaqueous medium containing a detergent and a hypochlorite and a polymerwherein said polymer does not destabilize the “chlorometric index” ofhypochlorites which are present; wherein said polymer is obtained by amethod of manufacturing homopolymers and/or copolymers, comprising:polymerizing ethylenically monounsaturated monomer(s) in an aqueoussolution in a reaction vessel containing compounds which contain aphosphorus atom of degree of oxidation less than 5, said phosphorouscompounds being introduced in amounts of 0.005-0.49 gram-atom phosphorusper mol of unsaturation in said ethylenically unsaturated monomer(s) inthe presence of hydrogen peroxide and in the absence of any agent(s)which decomposes hydrogen peroxide thereby forming free radicals, in theabsence of any other generator of free radicals, and in the absence ofany per salt and/or any other transfer agent; wherein for each monomer,the residual monomer concentration is less than or equal to 300 ppm,based on the weight of the raw product; wherein the dry matter contentis at least 38%; and wherein these constraints apply regardless of themonomer composition.
 7. A method of cleaning or suspending a zeolite,comprising: employing a polymer as a stabilizer for the zeolitesuspensions or as a builder in the detergent solution; wherein saidpolymer is obtained by a method of manufacturing homopolymers and/orcopolymers, comprising: polymerizing ethylenically monounsaturatedmonomer(s) in an aqueous solution in a reaction vessel containingcompounds which contain a phosphorus atom of degree of oxidation lessthan 5, said phosphorous compounds being introduced in amounts of0.005-0.49 gram-atom phosphorus per mol of unsaturation in saidethylenically unsaturated monomer(s) in the presence of hydrogenperoxide and in the absence of any agent(s) which decomposes hydrogenperoxide thereby forming free radicals, in the absence of any othergenerator of free radicals, and in the absence of any per salt and/orany other transfer agent; wherein for each monomer, the residual monomerconcentration is less than or equal to 300 ppm, based on the weight ofthe raw product; wherein the dry matter content is at least 38%; andwherein these constraints apply regardless of the monomer composition.8. An aqueous suspension of mineral material containing a polymer;wherein said polymer is obtained by a method of manufacturinghomopolymers and/or copolymers, comprising: polymerizing ethylenicallymonounsaturated monomer(s) in an aqueous solution in a reaction vesselcontaining compounds which contain a phosphorus atom of degree ofoxidation less than 5, said phosphorous compounds being introduced inamounts of 0.005-0.49 gram-atom phosphorus per mol of unsaturation insaid ethylenically unsaturated monomer(s) in the presence of hydrogenperoxide and in the absence of any agent(s) which decomposes hydrogenperoxide thereby forming free radicals, in the absence of any othergenerator of free radicals, and in the absence of any per salt and/orany other transfer agent; wherein for each monomer, the residual monomerconcentration is less than or equal to 300 ppm, based on the weight ofthe raw product; wherein the dry matter content is at least 38%; andwherein these constraints apply regardless of the monomer composition.9. A method of forming an aqueous suspension of a mineral material,comprising: employing a polymer as the suspending agent in the sectorsof paper, paints, ceramics, drilling muds, pending agent, or the sectorof detergents and washing; wherein said polymer is obtained by a methodof manufacturing homopolymers and/or copolymers, comprising:polymerizing ethylenically monounsaturated monomer(s) in an aqueoussolution in a reaction vessel containing compounds which contain aphosphorus atom of degree of oxidation less than 5, said phosphorouscompounds being introduced in amounts of 0.005-0.49 gram-atom phosphorusper mol of unsaturation in said ethylenically unsaturated monomer(s) inthe presence of hydrogen peroxide and in the absence of any agent(s)which decomposes hydrogen peroxide thereby forming free radicals, in theabsence of any other generator of free radicals, and in the absence ofany per salt and/or any other transfer agent; wherein for each monomer,the residual monomer concentration is less than or equal to 300 ppm,based on the weight of the raw product; wherein the dry matter contentis at least 38%; and wherein these constraints apply regardless of themonomer composition.